Legislators discuss Bayou Corne sinkhole

Published: Tuesday, February 19, 2013 at 9:14 p.m.

Last Modified: Tuesday, February 19, 2013 at 9:14 p.m.

BATON ROUGE — As an array of small explosives and even smaller microphones are used to map the ground deep under the Assumption Parish sinkhole, some residents say they never want to return to nearby Bayou Corne.

Facts

At a meeting Tuesday, lawmakers heaped pressure on Texas Brine — the company they deem responsible for the sinkhole — by asking its representatives to create a process to buy residents' properties.

Several of the estimated 350 people under an evacuation order gave teary testimony to the Joint Committee on Natural Resources and Environment.

“I cry going to work when I pass my home. I lay down at night and cry wanting to be at my house,” said Bayou Corne resident Candy Blanchard, who has been out of her home since the evacuation order was issued Aug. 3. “I don't feel safe, and I won't feel safe there again. I want Texas Brine to step up and start talking to us as individuals.”

Much of Tuesday's discussion centered on the idea of buying out residents who might be too fearful to return or have had property investments ruined by the hole.

“Bayou Corne will always be associated with this,” said Carl Dugas, who has lived in the area for 30 years. “Texas Brine is holding two of my homes hostage right now. I can't sell them. I can't borrow money against them.”

Dennis Landry, a resident and property developer in the neighborhood, added that Texas Brine should also compensate those who do not want to move for their decimated property values.

Pressed about potential buyouts, Bruce Martin, Texas Brine vice president of operations, did not commit to anything, other than saying his company is focusing on containing and understanding the sinkhole.

“I know there are some residents who want to be bought out and some who do not,” Martin said. “We have to focus on response activities.”

Martin urged residents to meet with the community relations liaison in Bayou Corne so the company can ascertain how many people are interested in some sort of proposal.

Another legislative committee meeting on the sinkhole will be held in March.

State officials described La. 70 near the sinkhole and Bayou Corne as a beehive of activity.

Trucks move on and off the otherwise quiet stretch, hauling in tons of earth for a nearly complete berm to contain the salty water and oil in the hole.

Thin, black torches sitting among the cypress trees are a reminder of the natural gas being vented from the ground below.

Inside some homes, residents live with monitors to detect any accumulation of gas. Other homes sit empty.

Tuesday was the 201st day an evacuation order has been in place for residents of Bayou Corne. While some residents want out, others just want peace of mind.

Scientists know the sinkhole was caused by a collapsed cavern — the top of which sits 3,400 feet below ground. The floor of the cavern sits about 5,600 feet below the surface.

That cavern was mined inside the Napoleonville Salt Dome, a naturally forming solid salt formation. Texas Brine mined the cavern by injecting water and then pulling the highly concentrated saltwater out for industrial applications.

Scientists believe the cavern was too close to the edge of the salt dome and outside pressure cause it to collapse, filling it with millions of cubic yards of earth that eventually led to the sinkhole. The collapse also let oil and gas sitting on the dome's edge to rise to the surface.

Before the evacuation order is lifted, John Boudreaux, Assumption Parish director of emergency operations, has said scientists must determine if the salt dome and other caverns within are stable, where gas has accumulated underground and if there is potential for another hole to open.

The cavern is about 80 percent full of displaced earth, officials said Tuesday. Considering the volume of the cavern, scientists said the hole itself will not grow enough to threaten residents more than 1,000 feet away.

There is the possibility of other voids below ground that could lead to another sinkhole, scientists said.

To answer these questions, contractors are creating a three-dimensional image to 7,000 feet below the surface.

A 2.8-square-mile zone has been charted above the dome's western flank.

That zone will be dotted with an array of 2,500 strategically placed shots and about 2,200 geophones.

The shots are typically small explosives buried 25 to 40 feet below the surface. Contractors are also using vibrosis trucks that shake the ground in 10-second intervals.

These shots will be recorded by the geophones, which are small microphones stuck in the ground.

“Sound travels at different speeds through different types of underground materials,” said Texas Brine spokesman Sonny Cranch.

That sound will eventually bounce back to the surface to be read by the geophones.

Scientists say they can map out any remaining underground voids, check the condition of the dome and determine where natural gas may be accumulating with the images created from the process.

“Using this many sensors close together, we are going to get some really high-resolution images,” said Hoyt O'Neal, crew supervisor for Boone Exploration, the contractor installing the equipment.

This imaging process is common in oil exploration, but not at this resolution. O'Neal said enough sensors are being used to map out a 23- square-mile area if this was an oil exploration job.

Cranch said the images should be created and processed by April.

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